The present invention relates to a combination drive having a linear drive device and a rotation drive device.
Until now, combined linear and rotation drives, also referred to as combination drives, have been mostly formed from two separate units. One of the units carries out the linear movement, while the other of the units carries out the rotation. The units are often also physically separated from one another. However, for the purposes of more recent developments, the two units have also been integrated in one housing.
FIG. 5 shows one such known combination drive in the form of a cross section. This combination drive is used, for example, for driving ink rollers in a printing mechanism. A linear motor 1, in the form of an external rotor, and a conventional rotating motor 2 are used in the drive. Both the linear motor and the rotating motor are in the form of synchronous motors with permanent-magnet excitation. The entire drive has two separate stators of different design, and two separate rotors of different design. However, the rotors are arranged on a common shaft.
One major disadvantage of the combination drive shown in FIG. 5 is that the entire rotor can move backwards and forwards only through a specific distance. This linear movement is fixed by the design for respective application. The drive can therefore be used only for that specific application. It is therefore not possible without changes to increase the linear movement without redesigning the motor. A further disadvantage is that the rotor cannot be removed from the motor in any desired manner for installation purposes.
A further disadvantage that has been found with the combination drive described above is that the two parts of the rotor must be designed differently. For this reason, the two stators must be arranged at an appropriate distance apart, thus predetermining a certain motor length which is too large for certain applications, or results in problems.
So-called hybrid reluctance motors are known in principle in the field of drives. In this case, the forces or torques of the motors are produced both by means of variable reluctance and by means of permanent magnets. This is mentioned, for example, in the VDI Reports 1269 dated May 1996.
Furthermore, German patent application DE 10 2004 045992.4 discloses a synchronous linear motor with a secondary part without any permanent magnets. The windings are incorporated in the primary part, adjacent to which the permanent magnets are also arranged.